Week 32 – Aug 9 – 13

2010 Mosquito Report: Week 32

Report based on data collected from traps deployed the week of August 9, 2010 through August 13, 2010. Report prepared by John Smith, Chan Suom, M.S., and Nate Boonisar.

1. Current mosquito activity/trend

CDC Light Traps:
Host seeking mosquito activity remains low throughout most of Norfolk County, although a few towns have reported average levels of mosquito activity:Bellingham, Braintree, Dedham, Foxboro, Medfield, Needham, Weymouth, and Wrentham.

Gravid Traps:
Gravid trap collections continue to be relatively low, but this week’s collection indicates a slight increase in mosquito activity with Bellingham, Canton, Dedham,Dover, Foxboro, Franklin, Holbrook, Medway, Millis, Norfolk, Norwood, Quincy, parts of Sharon, parts of Walpole, and Wrentham returning average numbers.

2. Current Predominant Species

CDC Light Traps:
The most predominant CDC-trapped mosquito in Norfolk County this week is Coquillettidia perturbans, but all indications point to relatively low collections compared to the historical average. Most specimens appeared aged, although there were a few collections that contained recently emerged Co. perturbans adults. Culex pipiens/restuans populations continue to be higher than average in Franklin. A population of Anopheles walkeri is higher than average in Franklin.

Gravid Traps:
Culex pipiens/restuans continue to dominate gravid traps, although their populations remain in decline as seen in recent weeks. Ochlerotatus japonicus populations are also in decline.

3. Comparison to previous season

Host seeking and gravid mosquito activity continue to be on the decline throughout most of Norfolk County but there is indication that activity may pick up in the following weeks. The forecast for outdoor activities is very good with minimal mosquito nuisance. The very low numbers of mosquitoes may provide a false sense of security in the wake of recent, historically high isolations of EEE virus in mosquitoes in southeastern Massachusetts. The first case of human EEE was just announced this weekend of a RI man contracting the virus in Southeastern Massachusetts. Precautions should be taken when prolonged outdoor activity is expected, not just in Southeastern Massachusetts but throughout the state.

4. Weather Summary

This week was hot and humid to start, then a cold front brought cooler and drier air towards the end of the week. This front also brought a wide-spread light rainfall to the county with amounts ranging from a tenth to quarter inch. Longer term rainfall deficits (30 and 60 days) continue around 50% of normal county-wide. The National Drought Mitigation Center continues to keep most of the county in an “Abnormally Dry” category.

Total weekly rainfall: 0.16 inches (-0.59 in.)
Total Monthly rainfall: 0.47 inches (-1.01 in.)
Total Yearly rainfall: 31.26 inches (+5.61 in.)

5. Number of requests for service

NCMCP received 6,401 calls year to date for service as of 8/13/10. NCMCP received 367 calls for service this week.

6. MCP/Commission response

NCMCP ground ULV applications have diminished steadily over the past several weeks in most of the county with the exception of eastern Quincy. Due to the heavy rain received last week field technicians were dispatched on Monday to treat the Broad Meadow area of Quincy. As a result of salt marsh flooding following the monthly high tide of August 11th field technicians also treated salt marshes in east Quincy and North Weymouth. Although overall the complaints are the highest since 2007, complaint calls are lower for the week and are now below levels recorded in 2009 for the same week. NCMCP continues to treat rain basins using a pouch with Bacillus sphaericus as the active ingredients.


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